The present invention relates to a control lever unit for operating equipment provided in a working vehicle.
Japanese Patent Application Publication No. 10-105267 discloses this type of control lever unit, which includes a grip for allowing displacement in at least two main operation directions and intermediate directions between the two main operation directions, a sliding piece, a cam plate with which the sliding piece is brought into contact, and a spring interposed between the grip and the sliding piece for causing a restoring force. The cam plate has a projection at each position with which the sliding piece is brought into contact when the grip (or lever) is displaced in the intermediate direction, thereby to cause larger change of length of the spring when the grip is displaced in the intermediate direction than when the grip is displaced in the main operation direction.
Therefore, it is practically impossible to erroneously operate the grip in the intermediate direction because strong resistance (a restoring force) is applied in operating the grip in the intermediate direction, which enables the lever to be operated accurately in the main operation direction.
It is when the lever is tilted to the maximum in the main operation direction that it is generally the easiest to apply operation force to the grip in this type of control lever unit. When the lever is thus in the maximum tilted position in the main operation direction, it is easy to displace the lever from the main operation direction toward the intermediate direction for some reason, depending on the direction of operation force applied by an operator. Consequently, erroneous operation of the lever frequently occurs to reduce working efficiency.
In this regard, in the control lever unit of Japanese Patent Application Publication No. 10-105267, strong resistance (a restoring force) is applied in operating the grip in the intermediate direction, so that it is regarded that the erroneous operation of the lever toward the side of the intermediate direction is avoided to some extent. In a state where the lever is tilted to the limit in the main operation direction as described above, however, it is frequent that particularly large force is applied to the lever. In this case, there is fear that the erroneous operation of the lever toward the side of the intermediate direction is performed in spite of the above strong resistance.
In the control lever unit of Japanese Patent Application Publication No. 10-105267 where strong resistance is applied in tilting the lever in the intermediate direction, when the lever is used to be actually tilted in the intermediate direction instead of the main operation direction, the lever is heavy in being tilted in the intermediate direction. Therefore, it is easy for an operator to be tired. In this regard, the control lever unit of the cited reference is far from preferable.
The present invention is directed to a control lever unit whose lever hardly causes erroneous operation toward the side of the intermediate direction even in a state that the lever is tilted to the maximum in the main operation direction and whose lever operated in the intermediate direction is not excessively heavy.